This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from my application entitled MICROWAVE OVEN AND METHOD THEREOF filed with the Korean Industrial Property Office on Jul. 11, 2001 and there duly assigned Ser. No. 2001-41457.
1. Field of the Invention
The present invention relates to a microwave oven and method for controlling the same, in which the presence of a user in a sensing area around the microwave oven is sensed, and the generation of high frequency waves and the illumination of a cooking chamber are controlled according to the presence of a user in the sensing area.
2. Description of the Conventional Art
In general, a microwave oven is an electronic appliance for heating and cooking food by irradiating high frequency microwaves to a sealed cavity wherein food is contained. Such a microwave oven generally includes a high voltage transformer and a magnetron. A control panel comprised of input and display parts is mounted on the front surface of an oven body to be conveniently manipulated by a user.
Referring to FIG. 5, the interior of an oven body 1 is partitioned into a machine chamber and a cooling chamber 4. A variety of electric devices including the machine chamber, a lamp 7, a cooling fan 8, a magnetron MGT, a high voltage transformer HVT, a high voltage condenser HVC, etc. are positioned in the machine chamber 2. A rotary tray 5 is mounted on the bottom of the cooling chamber 4 to hold food, and a door 3 is rotatably attached to one side of the oven body 1 to open and close the cooling chamber 4. A control panel 6 is provided on the front surface of the oven body 1 in front of the machine chamber 2.
A reference numeral 3a designates a latch, which is inserted into a recess 3b when the door 3 is closed and removed from the recess 3b when the door 3 is opened. A microswitch (not shown) inputs a door opening/closing sensing signal to control means (not shown) by the operation of the latch 3a. Accordingly, the control means recognizes the opening or closing of the door 3, and controls the operation of the magnetron to selectively stop the generation of high frequency waves and generate high frequency waves.
However, although a microwave oven is provided with a shield structure that is capable of preventing high frequency waves generated by a magnetron from leaking out of a cooking chamber, there are persons who have fears that the microwaves may be discharged from the cooking chamber. Some persons, such as housewives and children, avoid using the microwave ovens for fear of leakage of microwaves.
Meanwhile, in the conventional microwave oven, a lamp 7 is automatically turned on to illuminate the cooking chamber 4 when the door 3 is opened, while a lamp 7 is automatically turned off when the door 3 is closed. Accordingly, when the door is kept opened due to a user""s carelessness, the lamp 7 is unnecessarily kept turned on, thereby wasting electric power.
Accordingly, the present invention has been made keeping in mind the above problems occurring in the conventional art, and an object of the present invention is to provide a microwave oven and method for controlling the same, which is capable of controlling the generation of high frequency waves according to the presence of a user in a sensing area, thereby eliminating a person""s fear of the leakage of high frequency waves.
Another object of the present invention is to provide a microwave oven and method for controlling the same, which is capable of controlling the operation of the lamp of the microwave oven according to the presence of a user in the sensing area, thereby preventing electric power from being wasted by a user""s carelessness.
In order to accomplish the above object, the present invention provides a microwave oven, the microwave oven being used to heat and cook food using high frequency waves generated by high frequency generating means provided in an oven body, comprising: body sensing means for detecting the presence of a user in a sensing area extended over a certain area in front of the oven body; first operating means for operating the high frequency generating means; and control means for controlling the first operating means to selectively start, stop and resume the operation of the high frequency wave generating means according to the presence of a user in the sensing area.
Preferably, the body sensing means is a non-contact optical sensor for detecting the presence of a user without contact with the user.
Preferably, the body sensing means is mounted on the oven body at a position such that it covers a desired sensing area.
Preferably, the body sensing means comprises an infrared sensor for detecting the presence of a user in the sensing area in such a way that infrared rays emitted from a light emitting element enter a light receiving element, and a signal processing unit for high-pass-filtering and amplifying infrared signals entering the light receiving element.
Preferably, the microwave oven further comprises a light guide member for widely diffusing emitted infrared rays over a sensing area and condensing refracted infrared rays.
Preferably, the light guide member consists of a wide-angle lens positioned in front of the light emitting element and a condensing lens positioned in front of the light receiving element.
Preferably, the microwave oven further comprises a lamp for illuminating the cooking chamber of the oven body, second operating means for operating the lamp, and door opening/closing means for detecting the opening and closing of the door, wherein the control means controls the second operating means to turn on or off the lamp according to the presence of a user in the sensing area while the door is closed.
Additionally, the present invention provides a method for controlling a microwave oven, the microwave oven being used to heat and cook food using high frequency waves generated by high frequency generating means provided in an oven body, comprising the steps of: a) controlling the operation of a lamp according to the presence of a user in a sensing area extended over a certain area in front of the oven body in a first operation mode of putting food into the oven body; b) controlling the operation of a magnetron according to the presence of a user in the sensing area in a second operation mode of performing a cooking operation for a predetermined cooking time period; and c) controlling the operation of the lamp according to the presence of a user in the sensing area in a third operation mode of taking out food from the oven body.
Preferably, the first and third operating modes each comprise the steps of: turning on the lamp if the user is present in the sensing area; and turning off the lamp if the user is not present in the sensing area.
Preferably, the second operation mode comprises the steps of: starting the magnetron if a user is not present in the sensing area; stopping the magnetron if a user is present in the sensing area; and resuming the operation of the magnetron if a user is not present in the sensing area before the cooking time period is terminated.